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2.
World Neurosurg ; 139: 558-566, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32376373

RESUMO

BACKGROUND: Anatomical variations of the course of the internal carotid artery (ICA) may complicate surgical clipping of posterior communicating artery (PCoA) aneurysms by narrowing the retrocarotid window. We evaluated the efficacy of the periclinoid surgical maneuvers for expanding the retrocarotid window and analyzed computed tomography angiography (CTA) data from patients with PCoA aneurysms to define parameters for low-coursing ICAs. METHODS: Using cadaveric specimens, standard pterional craniotomies were fashioned and extradural or intradural periclinoid surgical maneuvers-cutting of the meningo-orbital band, anterior clinoidectomy, and cutting of the distal dural ring (DDR)-were performed, and their relative advantages for expanding the retrocarotid window were assessed. Additionally, preoperative CTA data from 24 patients with PCoA aneurysms used to calculate the angles of the ICA relative to the skull base. RESULTS: Periclinoid maneuvers, especially the anterior clinoidectomy, provided additional exposure of the retrocarotid space. Cutting of the DDR allowed for partial mobilization of the ICA and widened the retrocarotid surgical window, enhancing maneuverability. The anterior clinoidectomy with cutting of the DDR allowed for enhanced exposure of the medial, middle, and posterolateral aspects of the retrocarotid space. Cutting the anterior petroclinoid fold and mobilizing cranial nerve III provided wide exposure of the lateral aspect of retrocarotid space. CONCLUSION: When clipping PCoA aneurysms in the presence of normal-coursing ICAs (approximately ≥30° ICA angle), a standard pterional craniotomy with anterior clinoidectomy and cutting of the DDR allows for substantial expansion of the retrocarotid window.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Carótida Interna/diagnóstico por imagem , Angiografia por Tomografia Computadorizada/métodos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Instrumentos Cirúrgicos , Idoso , Artéria Carótida Interna/fisiopatologia , Humanos , Aneurisma Intracraniano/fisiopatologia , Masculino
3.
Am J Physiol Heart Circ Physiol ; 318(6): H1401-H1409, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32357114

RESUMO

The survival rate of patients with ischemic heart disease (IHD) is increasing. However, survivors experience increased risk for neurological complications. The mechanisms for this increased risk are unknown. We tested the hypothesis that patients with IHD have greater carotid and cerebrovascular stiffness, and these indexes predict white matter small vessel disease. Fifty participants (age, 40-78 yr), 30 with IHD with preserved ejection fraction and 20 healthy age-matched controls, were studied using ultrasound imaging of the common carotid artery (CCA) and middle cerebral artery (MCA), as well as magnetic resonance imaging (T1, T2-FLAIR), to measure white matter lesion volume (WMLv). Carotid ß-stiffness provided the primary measure of peripheral vascular stiffness. Carotid-cerebral pulse wave transit time (ccPWTT) provided a marker of cerebrovascular stiffness. Pulsatility index (PI) and resistive index (RI) of the MCA were calculated as measures of downstream cerebrovascular resistance. When compared with controls, patients with IHD exhibited greater ß-stiffness [8.5 ± 3.3 vs. 6.8 ± 2.2 arbitrary units (AU); P = 0.04], MCA PI (1.1 ± 0.20 vs. 0.98 ± 0.18 AU; P = 0.02), and MCA RI (0.66 ± 0.06 vs. 0.62 ± 0.07 AU; P = 0.04). There was no difference in WMLv between IHD and control groups (0.95 ± 1.2 vs. 0.86 ± 1.4 mL; P = 0.81). In pooled patient data, WMLv correlated with both ß-stiffness (R = 0.34, P = 0.02) and cerebrovascular ccPWTT (R = -0.43, P = 0.02); however, ß-stiffness and ccPWTT were not associated (P = 0.13). In multivariate analysis, WMLv remained independently associated with ccPWTT (P = 0.02) and carotid ß-stiffness (P = 0.04). Patients with IHD expressed greater ß-stiffness and cerebral microvascular resistance. However, IHD did not increase risk of WMLv or cerebrovascular stiffness. Nonetheless, pooled data indicate that both carotid and cerebrovascular stiffness are independently associated with WMLv.NEW & NOTEWORTHY This study found that patients with ischemic heart disease (IHD) with preserved ejection fraction and normal blood pressures exhibit greater carotid ß-stiffness, as well as middle cerebral artery pulsatility and resistive indexes, than controls. White matter lesion volume (WMLv) was not different between vascular pathology groups. Cerebrovascular pulse wave transit time (ccPWTT) and carotid ß-stiffness independently associate with WMLv in pooled participant data, suggesting that regardless of heart disease history, ccPWTT and ß-stiffness are associated with structural white matter damage.


Assuntos
Artéria Carótida Primitiva/diagnóstico por imagem , Artéria Cerebral Média/diagnóstico por imagem , Isquemia Miocárdica/diagnóstico por imagem , Rigidez Vascular/fisiologia , Substância Branca/diagnóstico por imagem , Adulto , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Artéria Carótida Primitiva/fisiopatologia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/fisiopatologia , Isquemia Miocárdica/fisiopatologia , Volume Sistólico , Ultrassonografia , Substância Branca/fisiopatologia
4.
Invest Ophthalmol Vis Sci ; 61(4): 3, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32271886

RESUMO

Purpose: We developed a combined biomechanical and hemodynamic model of the human eye to estimate blood flow and oxygen concentration within the lamina cribrosa (LC) and rank the factors that influence LC oxygen concentration. Methods: We generated 5000 finite-element eye models with detailed microcapillary networks of the LC and computed the oxygen concentration of the lamina retinal ganglion cell axons. For each model, we varied the intraocular pressure (IOP) from 10 mm Hg to 55 mm Hg in 5-mm Hg increments, the cerebrospinal fluid pressure (13 ± 2 mm Hg), cup depth (0.2 ± 0.1 mm), scleral stiffness (±20% of the mean values), LC stiffness (0.41 ± 0.2 MPa), LC radius (1.2 ± 0.12 mm), average LC pore size (5400 ± 2400 µm2), the microcapillary arrangement (radial, isotropic, or circumferential), and perfusion pressure (50 ± 9 mm Hg). Blood flow was assumed to originate from the LC periphery and drain via the central retinal vein. Finally, we performed linear regressions to rank the influence of each factor on the LC tissue oxygen concentration. Results: LC radius and perfusion pressure were the most important factors in influencing the oxygen concentration of the LC. IOP was another important parameter, and eyes with higher IOP had higher compressive strain and slightly lower oxygen concentration. In general, superior-inferior regions of the LC had significantly lower oxygen concentration than the nasal-temporal regions, resulting in an hourglass pattern of oxygen deficiency. Conclusions: To the best of our knowledge, this study is the first to implement a comprehensive hemodynamical model of the eye that accounts for the biomechanical forces and morphological parameters of the LC. The results provide further insight into the possible relationship of biomechanical and vascular pathways leading to ischemia-induced optic neuropathy.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Disco Óptico/irrigação sanguínea , Oxigênio/sangue , Fluxo Sanguíneo Regional/fisiologia , Células Ganglionares da Retina/metabolismo , Axônios/metabolismo , Fenômenos Biomecânicos/fisiologia , Simulação por Computador , Análise de Elementos Finitos , Hemodinâmica/fisiologia , Humanos , Pressão Intraocular/fisiologia , Consumo de Oxigênio/fisiologia , Esclera/metabolismo , Estresse Mecânico
5.
Medicine (Baltimore) ; 99(17): e19897, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32332665

RESUMO

This study aimed to evaluate the impact of the echocardiographic parameter ratio E/E' on the late recurrence of paroxysmal atrial fibrillation in patients after receiving radiofrequency catheter ablation.We retrospectively examined total of 288 paroxysmal atrial fibrillation (PAF) patients that underwent a preliminary radiofrequency catheter ablation (RFCA) in our hospital. During the first phase in this study, the patients were divided into 2 groups upon AF recurrence after RFCA: Recurrent group, n = 67 patients with rapid trial arrhythmia that lasted for more than 30 seconds at 3 months after RFCA and the Nonrecurrent group, n = 221. The clinical conditions were compared between the 2 groups. During the second phase of this study, based on the results in the first phase, the patients were divided into another 2 groups according to whether the ratio of E/E' ≥13 .45: Higher ratio of E/E' group, n = 55 and Lower ratio of E/E' group n = 233. The late AF recurrent rates were also compared between the 2 groups.During the first phase, the univariate analysis indicated that the risk factors(P < .05)for PAF late recurrence included early recurrence, E', and the ratio E/E'. The Cox multivariate analysis showed that the ratio of E/E' and early recurrence were the independent predictors for late PAF recurrence. The ratio of E/E' that was cut off at 13.45 also predicted atrial tachyarrhythmia recurrence with 40.3% sensitivity and 87.3% specificity. In the second phase, after completing the 1:1 matching, the Kaplan-Meier analysis indicated that the ratio of E/E' ≥ 13.45 was associated with further recurrences after RFCA (log-rank P = .009), compared to the patients with a ratio of E/E' < 13.45. The univariate Cox analysis indicated that an elevated ratio of E/E'(≥13.45) was the independent predictor for late PAF recurrence (HR = 3.322, 95%CI: 1.560-7.075, P = .002). However, the ratio of E/E' cut off at 13.25 predicted atrial tachyarrhythmia recurrence with 75% sensitivity and 62.2% specificity.The ratio of E/E' ≥ 13.25 is an important predictor of the late recurrence of paroxysmal atrial fibrillation (PAF) after radiofrequency catheter ablation (RFCA).


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/efeitos adversos , Ecocardiografia/instrumentação , Assistência ao Convalescente , Idoso , Fibrilação Atrial/etiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Ablação por Cateter/métodos , China , Ecocardiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Recidiva , Estudos Retrospectivos , Fatores de Risco
6.
Transfusion ; 60(5): 1032-1041, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32237236

RESUMO

BACKGROUND: Great deformability allows red blood cells (RBCs) to flow through narrow capillaries in tissues. A number of microfluidic devices with capillary-like microchannels have been developed to monitor storage-related impairment of RBC deformability during blood banking operations. This proof-of-concept study describes a new method to standardize and improve reproducibility of the RBC deformability measurements using one of these devices. STUDY DESIGN AND METHODS: The rate of RBC flow through the microfluidic capillary network of the microvascular analyzer (MVA) device made of polydimethylsiloxane was measured to assess RBC deformability. A suspension of microbeads in a solution of glycerol in phosphate-buffered saline was developed to be used as an internal flow rate reference alongside RBC samples in the same device. RBC deformability and other in vitro quality markers were assessed weekly in six leukoreduced RBC concentrates (RCCs) dispersed in saline-adenine-glucose-mannitol additive solution and stored over 42 days at 4°C. RESULTS: The use of flow reference reduced device-to-device measurement variability from 10% to 2%. Repeated-measure analysis using the generalized estimating equation (GEE) method showed a significant monotonic decrease in relative RBC flow rate with storage from Week 0. By the end of storage, relative RBC flow rate decreased by 22 ± 6% on average. CONCLUSIONS: The suspension of microbeads was successfully used as a flow reference to increase reproducibility of RBC deformability measurements using the MVA. Deformability results suggest an early and late aging phase for stored RCCs, with significant decreases between successive weeks suggesting a highly sensitive measurement method.


Assuntos
Deformação Eritrocítica/fisiologia , Eritrócitos/citologia , Eritrócitos/fisiologia , Dispositivos Lab-On-A-Chip/normas , Técnicas Analíticas Microfluídicas , Bancos de Sangue/métodos , Bancos de Sangue/normas , Velocidade do Fluxo Sanguíneo/fisiologia , Preservação de Sangue/efeitos adversos , Preservação de Sangue/métodos , Preservação de Sangue/normas , Criopreservação , Contagem de Eritrócitos/instrumentação , Contagem de Eritrócitos/métodos , Contagem de Eritrócitos/normas , Citometria de Fluxo/instrumentação , Citometria de Fluxo/métodos , Citometria de Fluxo/normas , Hemólise , Humanos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Técnicas Analíticas Microfluídicas/normas , Estudo de Prova de Conceito , Reprodutibilidade dos Testes , Fatores de Tempo
7.
Am J Cardiol ; 126: 82-88, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32327190

RESUMO

Transcatheter aortic valve implantation (TAVI) theoretically increases cardiac output and renal blood flow, and renal function (RF) recovers in patients with severe aortic valve stenosis (AS). However, procedural steps of TAVI including contrast use potentially damage RF. Data describing RF improvements after TAVI in patients with chronic kidney disease (CKD) are lacking. We aimed to determine preoperative predictors of RF improvement after TAVI in severe AS patients with CKD. This observational study included 121 consecutive patients with severe AS and CKD (grade ≥3) who underwent TAVI. The patients were grouped according to their RF improvement after TAVI that was defined as an estimated glomerular filtration rate (eGFR) increase ≥10% at discharge from their preoperative level. Sixty-five patients' (54%) RF improved after TAVI. Patients with lower preoperative eGFR tended to achieve greater eGFR increases after TAVI (r = -0.17, p = 0.059). After adjustments for the factors that were significant in the univariate analysis, the preoperative mean transaortic pressure gradient (TAPG) (adjusted odds ratio, 1.03; 95% confidence interval, 1.00 to 1.07) and E/e' (adjusted odds ratio, 0.93; 95% confidence interval, 0.88 to 0.99) independently predicted RF improvement. The cut-off values for the preoperative mean TAPG and E/e' for an RF improvement after TAVI were 47.0 mm Hg and 13.8, respectively. In conclusion, preoperatively, a high mean TAPG and a low E/e' could predict RF improvement after TAVI in patients with CKD.


Assuntos
Estenose da Valva Aórtica/cirurgia , Insuficiência Renal Crônica/fisiopatologia , Substituição da Valva Aórtica Transcateter , Idoso de 80 Anos ou mais , Estenose da Valva Aórtica/fisiopatologia , Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Estudos de Coortes , Circulação Coronária/fisiologia , Feminino , Taxa de Filtração Glomerular/fisiologia , Humanos , Masculino
8.
Arch Gynecol Obstet ; 301(5): 1199-1205, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32303887

RESUMO

PURPOSE: The aim of our study was to compare the maternal arterial stiffness in pregnant women with diabetic disease, hypertension and those with normal pregnancies. METHODS: A cross-sectional study was performed involving 65 pregnant women with diabetic disease (DD group), 26 pregnant women with hypertension (RR group) and 448 women with normal pregnancies (control group). The augmentation index (AIx) and the pulse wave velocity (PWV) of the right carotid artery were assessed using non-invasive sonographic wave intensity analysis. Furthermore, the reliability of the measurements was evaluated in 21 healthy women. RESULTS: Compared with the controls, the AIx and PWV were increased in the DD group [11.0 (interquartile range, IQR 7.3, 15.2) vs. 5.7 (IQR 2.4, 9.3), P < 0.001; 5.7 (IQR 5.1, 6.4) vs. 5.2 (IQR 4.6, 6.1), P = 0.001; respectively] and the RR group [9.3 (IQR 6.6, 11.5) vs. 5.7 (IQR 2.4, 9.3), P < 0.001; 7.1 (6.3, 7.9) vs. 5.2 (IQR 4.6, 6.1), P < 0.001; respectively]. The intraclass and interclass correlation coefficients were good to excellent for the AIx (ICC: 0.91, P < 0.001 and 0.74, P < 0.002; respectively) and PWV measurements (ICC: 0.71, P < 0.004 and 0.70, P < 0.005; respectively). CONCLUSION: Pregnancies complicated by diabetic disease or hypertension are associated with increased maternal arterial stiffness. The importance of wave intensity analysis needs to be verified and larger studies are needed to establish both normal and cutoff values that may be relevant for clinical decisions.


Assuntos
Artérias/fisiopatologia , Velocidade do Fluxo Sanguíneo/fisiologia , Diabetes Gestacional/fisiopatologia , Hipertensão Induzida pela Gravidez/fisiopatologia , Fluxo Pulsátil/fisiologia , Análise de Onda de Pulso/métodos , Rigidez Vascular/fisiologia , Adulto , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/fisiopatologia , Diabetes Gestacional/epidemiologia , Feminino , Humanos , Hipertensão/epidemiologia , Hipertensão Induzida pela Gravidez/epidemiologia , Pessoa de Meia-Idade , Gravidez , Reprodutibilidade dos Testes , Fatores de Risco , Ultrassonografia
9.
Medicine (Baltimore) ; 99(15): e19805, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32282745

RESUMO

RATIONALE: The percutaneous catheterization of central veins is widely applied in patients with end-stage renal diseases as a permanent vascular access. To our knowledge, inadvertent placement of a hemodialysis catheter into the azygos vein through the left internal jugular vein is not described. PATIENT CONCERNS: A 72-year-old female patient was admitted to the hospital for replacement of another new tunneled hemodialysis catheter due to poor flow in the left internal jugular vein tunneled catheter during hemodialysis. DIAGNOSIS: The catheter tip was incorrectly positioned into the azygos vein as confirmed by conventional anteroposterior and lateral chest radiographs. INTERVENTIONS: The catheter was removed and replaced under Digital Subtraction Angiography. OUTCOMES: The catheter tip was finally placed in the proper position. LESSIONS: The insertion of central vein catheterization is not always in suitable position especially through left jugular vein in hemodialysis patients. DSA technology should be performed to confirm the correct position of the tip and to ensure good blood flow.


Assuntos
Veia Ázigos/diagnóstico por imagem , Cateteres Venosos Centrais/efeitos adversos , Veias Jugulares/diagnóstico por imagem , Radiografia Torácica/métodos , Diálise Renal/efeitos adversos , Idoso , Angiografia Digital/métodos , Veia Ázigos/cirurgia , Velocidade do Fluxo Sanguíneo/fisiologia , Cateteres Venosos Centrais/normas , Feminino , Humanos , Veias Jugulares/cirurgia , Diálise Renal/métodos , Resultado do Tratamento
10.
Circ Cardiovasc Imaging ; 13(3): e009539, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32164454

RESUMO

BACKGROUND: Inflammation and microcalcification are interrelated processes contributing to atherosclerotic plaque vulnerability. Positron-emission tomography can quantify these processes in vivo. This study investigates (1) 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) uptake in culprit versus nonculprit carotid atheroma, (2) spatial distributions of uptake, and (3) how macrocalcification affects this relationship. METHODS: Individuals with acute ischemic stroke with ipsilateral carotid stenosis of ≥50% underwent FDG-positron-emission tomography and NaF-positron-emission tomography. Tracer uptake was quantified using maximum tissue-to-background ratios (TBRmax) and macrocalcification quantified using Agatston scoring. RESULTS: In 26 individuals, median most diseased segment TBRmax (interquartile range) was higher in culprit than in nonculprit atheroma for both FDG (2.08 [0.52] versus 1.89 [0.40]; P<0.001) and NaF (2.68 [0.63] versus 2.39 [1.02]; P<0.001). However, whole vessel TBRmax was higher in culprit arteries for FDG (1.92 [0.41] versus 1.71 [0.31]; P<0.001) but not NaF (1.85 [0.28] versus 1.79 [0.60]; P=0.10). NaF uptake was concentrated at carotid bifurcations, while FDG was distributed evenly throughout arteries. Correlations between FDG and NaF TBRmax differed between bifurcations with low macrocalcification (rs=0.38; P<0.001) versus high macrocalcification (rs=0.59; P<0.001). CONCLUSIONS: This is the first study to demonstrate increased uptake of both FDG and NaF in culprit carotid plaques, with discrete distributions of pathophysiology influencing vulnerability in vivo. These findings have implications for our understanding of the natural history of the disease and for the clinical assessment and management of carotid atherosclerosis.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Isquemia Encefálica/etiologia , Artérias Carótidas/diagnóstico por imagem , Estenose das Carótidas/diagnóstico , Placa Aterosclerótica/diagnóstico , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Idoso , Isquemia Encefálica/diagnóstico , Estenose das Carótidas/complicações , Estenose das Carótidas/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Placa Aterosclerótica/complicações , Placa Aterosclerótica/fisiopatologia , Estudos Prospectivos
11.
Ultrasonics ; 104: 106093, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32151876

RESUMO

Color Doppler (CD) ultrasound has been commonly employed in biomedical field to get hemodynamic information. However, reliable diagnostic evaluation and criteria for vascular diseases may not be provided due to technical limitations of CD, including single-directional measurement, aliasing, and limited imaging conditions. In this study, adaptive hybrid (AH) scheme is proposed to enhance measurement accuracy of conventional CD. It can improve the accuracy of velocity field measurement by replacing erroneous vectors in the measured CD results with the correct vectors obtained from a speckle image velocimetry (SIV) technique. The performance of the proposed AH technique was validated through in vitro experiments for various flow rates and insonation angle conditions, comparing conventional velocimetry techniques. The in vitro experiments demonstrated that the AH technique could measure flow velocity with better accuracy than the CD with bias errors of below 0.7 mm/s. The clinical applicability of the AH was also validated by measuring venous flows at human lower extremity, checking constant volumetric flow rates. Flow rates measured by the AH were maintained along the vein, while the CD and SIV results varied. As a result, the AH can provide improved measurement accuracy without installing a new supplementary equipment. It would be effectively utilized for analyzing flow dynamics and diagnosing valve-related disease.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Extremidade Inferior/irrigação sanguínea , Ultrassonografia Doppler em Cores/métodos , Doenças Vasculares/diagnóstico por imagem , Adulto , Algoritmos , Feminino , Humanos , Aumento da Imagem , Masculino , Imagens de Fantasmas , Transdutores
12.
J Sports Sci ; 38(7): 751-758, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32106780

RESUMO

Blood flow changes in response to exercise have been attributed, among other factors, to the effect of vasodilators factors on the microvasculature, suggesting a close relationship between small blood vessels and conducting arteries. The main purpose of this study was to determine the relationship between the changes in near infrared spectroscopy (NIRS)-derived total haemoglobin ([tHb]) and muscle oxygen saturation (SmO2) signals and femoral artery blood flow in response to resistance exercise at fast- and slow-velocity muscle contraction. The study randomised crossover design included twelve participants. NIRS and blood flow measurements were continuously monitored before, during, and 5 min after the exercise protocol. There was a significant correlation between [tHb] reperfusion slope ([tHb]slope) and peak blood flow (BFpeak) after slow- and fast-velocity muscle contraction (r = 0.83, p = 0.0008 and r = 0.72, p = 0.0080, respectively). No significant correlation existed between the SmO2 reperfusion slope (SmO2_slope) and BFpeak after both slow- and fast-velocity muscle contraction exercise (r = -0.46, p = 0.1253 and r = 0.33, p = 0.2841, respectively). This study demonstrated a strong relationship between the NIRS-derived [tHb] and Doppler ultrasound BF during the recovery period of dynamic resistance exercise at both slow- and fast-velocity contraction.


Assuntos
Hemoglobinas/metabolismo , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/diagnóstico por imagem , Oxiemoglobinas/metabolismo , Treinamento de Resistência/métodos , Espectroscopia de Luz Próxima ao Infravermelho , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos Cross-Over , Artéria Femoral/fisiologia , Humanos , Hiperemia/fisiopatologia , Microcirculação/fisiologia , Contração Muscular/fisiologia , Consumo de Oxigênio/fisiologia , Fluxo Sanguíneo Regional , Ultrassonografia Doppler
13.
Eur J Vasc Endovasc Surg ; 59(4): 625-634, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32008931

RESUMO

OBJECTIVE: The subcutaneous venous network (SVN) is difficult to see with the naked eye. Near infrared illumination (NIr-I) claims to improve this. The aims of this observational study were to investigate whether there are differences between the different methods; to quantify the length and diameter of SVNs; and to confirm if they differ between C0A and C1 CEAP limbs. METHODS: In total, 4 796 images, half of them from the visible spectrum (VS) and the other half from the nearninfrared spectrum (NIrS), belonging to 109 females (C0A: n = 50; C1 CEAP: n = 59) were used to establish the morphological characteristics of the SVN by visual analysis. With Photoshop CS4, SVN diameters and lengths were obtained by digital analysis of 3 052 images, once the images of whole extremities were excluded. RESULTS: On NIr-I, the diameters, trajectories, and colouration of SVNs of C1 limbs appeared more irregular than SVNs of C0A limbs. Compared with the VS images, NIr-I allowed visualisation of a greater length of the SVN in both groups (p < .010). This capacity varied from 2.6 ± 0.9 times (C1) to 16.2 ± 11.9 (C0A). While the SVN length seen in the VS images from C1 limbs was greater than observed in C0A limbs (p < .001), differences between NIr-I images only existed in the lateral part of the lower leg (p = .016). With NIr-I, the median diameter of the C1 CEAP SVN veins was 5.8 mm (interquartile range [IQR] 4.3-7.5 mm), while the median diameter in C0A SVN limbs was 2.6 mm (IQR 2.0-3.6 mm) (p < .001). CONCLUSION: The NIr-I reveals the characteristics of the SVN better than the naked eye. Further studies are required to determine the significance of the changes in the SVN in C0A and C1 limbs, and the factors causing them.


Assuntos
Extremidades/irrigação sanguínea , Varizes/diagnóstico por imagem , Veias/diagnóstico por imagem , Insuficiência Venosa/cirurgia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Extremidades/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional/fisiologia , Ultrassonografia Doppler Dupla/métodos , Varizes/cirurgia , Insuficiência Venosa/diagnóstico por imagem
14.
Transfusion ; 60(3): 607-612, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32037555

RESUMO

BACKGROUND: Peripheral venous access (PVA) devices for apheresis should be selected to provide enough flow with the least vein damage, but little information is available about PVA devices blood flow rates. The aim of this study was to know the blood flow rates provided by the most frequent PVA devices used in apheresis procedures. STUDY DESIGN AND METHODS: An experimental study was designed to simulate a plasma exchange procedure using citrated whole blood (WB). Two steel needles (16- and 17-gauge [G]) and six plastic cannulas (16G, 17G, two 18G, 20G, and 22G) were analyzed. The hematocrit of the WB was adjusted to 45%, 40%, 35%, 30%, and 25%. The separated plasma from the WB was used as replacement fluid. RESULTS: Blood flow rate (inlet/return, mL/min) for 16G and 17G devices with a hematocrit of 45% was 142/142 (maximum admitted by separator); one of the 18G cannulas reached 142/142 and the other one reached 117/140; the 20G cannula reached 78/94; and the 22G reached 45/55. A hematocrit reduction from 45% to 25% increased the flow rate (when possible) over 22% (range: 14%-30%). CONCLUSIONS: PVA devices with a size of 16-18G provided the maximum flow admitted by the apheresis system. The 20G provided flow rates for a significant number of procedures, and 22G could be used in some procedures. The hematocrit should be taken into account when selecting the PVA device since, at hematocrit of 25%, the flow can be from 14% to 30% higher than flow rates reached with blood at hematocrit of 45%.


Assuntos
Remoção de Componentes Sanguíneos , Velocidade do Fluxo Sanguíneo/fisiologia , Hematócrito , Humanos , Agulhas
15.
Am J Physiol Regul Integr Comp Physiol ; 318(3): R605-R618, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32022580

RESUMO

Reactive hyperemia is a well-established technique for noninvasive assessment of peripheral microvascular function and a predictor of all-cause and cardiovascular morbidity and mortality. In its simplest form, reactive hyperemia represents the magnitude of limb reperfusion following a brief period of ischemia induced by arterial occlusion. Over the past two decades, investigators have employed a variety of methods, including brachial artery velocity by Doppler ultrasound, tissue reperfusion by near-infrared spectroscopy, limb distension by venous occlusion plethysmography, and peripheral artery tonometry, to measure reactive hyperemia. Regardless of the technique used to measure reactive hyperemia, blunted reactive hyperemia is believed to reflect impaired microvascular function. With the advent of several technological advancements, together with an increased interest in the microcirculation, reactive hyperemia is becoming more common as a research tool and is widely used across multiple disciplines. With this in mind, we sought to review the various methodologies commonly used to assess reactive hyperemia and current mechanistic pathways believed to contribute to reactive hyperemia and reflect on several methodological considerations.


Assuntos
Hiperemia/fisiopatologia , Isquemia/fisiopatologia , Microcirculação/fisiologia , Vasodilatação/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Braquial/fisiopatologia , Humanos
16.
Am Heart J ; 222: 139-146, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32062172

RESUMO

BACKGROUND: It remains uncertain if invasive coronary physiology beyond fractional flow reserve (FFR) can refine lesion selection for revascularization or provide additional prognostic value. Coronary flow reserve (CFR) equals the ratio of hyperemic to baseline flow velocity and has a wealth of invasive and noninvasive data supporting its validity. Because of fundamental physiologic relationships, binary classification of FFR and CFR disagrees in approximately 30%-40% of cases. Optimal management of these discordant cases requires further study. AIM: The aim of the study was to determine the prognostic value of combined FFR and CFR measurements to predict the 24-month rate of major adverse cardiac events. Secondary end points include repeatability of FFR and CFR, angina burden, and the percentage of successful FFR/CFR measurements which will not be excluded by the core laboratory. METHODS: This prospective, nonblinded, nonrandomized, and multicenter study enrolled 455 subjects from 12 sites in Europe and Japan. Patients underwent physiologic lesion assessment using the 0.014" Philips Volcano ComboWire XT that provides simultaneous pressure and Doppler velocity sensors. Intermediate coronary lesions received only medical treatment unless both FFR (≤0.8) and CFR (<2.0) were below thresholds. The primary outcome is a 24-month composite of death from any cause, myocardial infarction, and revascularization. CONCLUSION: The DEFINE-FLOW study will determine the prognostic value of invasive CFR assessment when measured simultaneously with FFR, with a special emphasis on discordant classifications. Our hypothesis is that lesions with an intact CFR ≥ 2.0 but reduced FFR ≤ 0.8 will have a 2-year outcome with medical treatment similar to lesions with FFR> 0.80 and CFR ≥ 2.0. Enrollment has been completed, and final follow-up will occur in November 2019.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Estenose Coronária/diagnóstico , Vasos Coronários/fisiopatologia , Reserva Fracionada de Fluxo Miocárdico/fisiologia , Monitorização Fisiológica/instrumentação , Idoso , Cateterismo Cardíaco/métodos , Estenose Coronária/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Ecocardiografia Doppler , Feminino , Seguimentos , Humanos , Masculino , Valor Preditivo dos Testes , Estudos Prospectivos , Reprodutibilidade dos Testes , Índice de Gravidade de Doença
17.
PLoS One ; 15(2): e0229105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084188

RESUMO

Brain artery velocities (Time-Averaged Maximum Mean Velocity, TAMMV) by Transcranial Doppler (TCD), hematocrit, hemoglobin, Red blood cell (RBC) Distribution Width (RDW) and RBC rigidity index (Ri), when reported together with their correlations, provide a accurate and useful diagnostic picture than blood viscosity measurements alone. Additionally, our study included a sixth parameter provided by TCD, the Gosling Pulsatility Index PI, which is an indicator of CBF (Cerebral Blood Flow) resistance. All these parameters are routine in Hematology except for values of Ri. The rigidity (Ri) of the RBC is the main rheological characteristic of the blood of Sickle Cell Anemia (SCA) patients and several pathologies. However, its quantification depends on many commercial and experimental techniques, none disseminated and predominant around the World. The difference in absorbance values of the blood, during the process of sedimentation in a microwell of a Microplate Reader, is a straightforward way of semi-quantifying the RBC rigidity Ri, since the fraction of irreversibly sickled red blood cells does not form rouleaux. Erythrocyte Rigidity Index (Ri) was calculated using initial absorbance Ainitial (6 s) and final Afinal (540 s), Ri = 1 / (Ai-Af). The Ri of 119 patients (2-17 y / o, M & F) SCA, SCC (Sickle Cell/hemoglobin C), SCD (Sickle Cell/hemoglobin D), Sß0thal (Sickle Cell/hemoglobin Beta Zero Thalassemia) and 71 blood donors (20-65 y / o, M & F) were measured in our laboratory while the five parameters (TAMMV and PI by TCD, Hct, Hb and RDW) were obtained from medical records. The in vitro addition of hydroxyurea (HU, 50mg /dl, n = 51 patients, and n = 8 healthy donors) in the samples decreased the rouleaux adhesion strength of both donor and patients' blood samples, leading to extraordinarily high Ri values. The correlation between the studied parameters was especially significant for the direct relationships between Ri, TAMMV, and PI.


Assuntos
Eritrócitos/citologia , Eritrócitos/metabolismo , Adolescente , Adulto , Idoso , Anemia Falciforme/metabolismo , Velocidade do Fluxo Sanguíneo/fisiologia , Criança , Pré-Escolar , Índices de Eritrócitos , Feminino , Hematócrito , Hemoglobinas/metabolismo , Humanos , Hidroxiureia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
18.
Am J Obstet Gynecol ; 222(6): 602.e1-602.e15, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31954701

RESUMO

BACKGROUND: Reference values for umbilical artery Doppler indices are used clinically to assess fetal well-being. However, many studies that have produced reference charts have important methodologic limitations, and these result in significant heterogeneity of reported reference ranges. OBJECTIVES: To produce international gestational age-specific centiles for umbilical artery Doppler indices based on longitudinal data and the same rigorous methodology used in the original Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. STUDY DESIGN: In Phase II of the INTERGROWTH-21st Project (the INTERBIO-21st Study), we prospectively continued enrolling pregnant women according to the same protocol from 3 of the original populations in Pelotas (Brazil), Nairobi (Kenya), and Oxford (United Kingdom) that had participated in the Fetal Growth Longitudinal Study. Women with a singleton pregnancy were recruited at <14 weeks' gestation, confirmed by ultrasound measurement of crown-rump length, and then underwent standardized ultrasound every 5±1 weeks until delivery. From 22 weeks of gestation umbilical artery indices (pulsatility index, resistance index, and systolic/diastolic ratio) were measured in a blinded fashion, using identical equipment and a rigorously standardized protocol. Newborn size at birth was assessed using the international INTERGROWTH-21st Standards, and infants had detailed assessment of growth, nutrition, morbidity, and motor development at 1 and 2 years of age. The appropriateness of pooling data from the 3 study sites was assessed using variance component analysis and standardized site differences. Umbilical artery indices were modeled as functions of the gestational age using an exponential, normal distribution with second-degree fractional polynomial smoothing; goodness of fit for the overall models was assessed. RESULTS: Of the women enrolled at the 3 sites, 1629 were eligible for this study; 431 (27%) met the entry criteria for the construction of normative centiles, similar to the proportion seen in the original fetal growth longitudinal study. They contributed a total of 1243 Doppler measures to the analysis; 74% had 3 measures or more. The healthy low-risk status of the population was confirmed by the low rates of preterm birth (4.9%) and preeclampsia (0.7%). There were no neonatal deaths and satisfactory growth, health, and motor development of the infants at 1 and 2 years of age were documented. Only a very small proportion (2.8%-6.5%) of the variance of Doppler indices was due to between-site differences; in addition, standardized site difference estimates were marginally outside this threshold in only 1 of 27 comparisons, and this supported the decision to pool data from the 3 study sites. All 3 Doppler indices decreased with advancing gestational age. The 3rd, 5th 10th, 50th, 90th, 95th, and 97th centiles according to gestational age for each of the 3 indices are provided, as well as equations to allow calculation of any value as a centile and z scores. The mean pulsatility index according to gestational age = 1.02944 + 77.7456*(gestational age)-2 - 0.000004455*gestational age3. CONCLUSION: We present here international gestational age-specific normative centiles for umbilical artery Doppler indices produced by studying healthy, low-risk pregnant women living in environments with minimal constraints on fetal growth. The centiles complement the existing INTERGROWTH-21st Standards for assessment of fetal well-being.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Idade Gestacional , Artérias Umbilicais/diagnóstico por imagem , Resistência Vascular/fisiologia , Adulto , Brasil , Desenvolvimento Infantil , Estudos de Coortes , Diástole , Feminino , Desenvolvimento Fetal , Humanos , Lactente , Recém-Nascido , Quênia , Estudos Longitudinais , Masculino , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Estudos Prospectivos , Valores de Referência , Sístole , Ultrassonografia Doppler em Cores , Ultrassonografia Doppler de Pulso , Ultrassonografia Pré-Natal , Artérias Umbilicais/fisiologia , Reino Unido , Adulto Jovem
19.
Am J Cardiol ; 125(5): 759-766, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31889522

RESUMO

Catheter ablation of atrial fibrillation (AF) is known to facilitate reverse remodeling of the left ventricle. However, factors that can improve the left ventricular (LV) systolic function remain elusive. In this study, we investigated factors related to LV ejection fraction (LVEF) improvement following AF ablation in patients with systolic dysfunction. A total of 140 patients with impaired LVEF (<50%) who underwent AF ablation were retrospectively evaluated. The primary outcome was LVEF improvement. A total of 68, 9, and 15 patients achieved LVEF improvement at 3, 6, and 12 months after AF ablation, respectively. Five patients achieved late LVEF improvement. The overall LVEF improvement rate was 69%. In the receiver operating characteristic curve analysis, the LV end-systolic volume (LVESVI) and early diastolic mitral annular velocity (e') had larger areas under the curve (0.79 and 0.75, respectively) than other echocardiographic parameters, and the most optimal cutoff values of LVESVI and e' were 49.8 ml/m2 and 5.4 cm/s, respectively. Moreover, preprocedural LVESVI ≤49.8 ml/m2 and e' ≥5.4 independently predicted the outcome after adjusting for confounders (hazard ratio 1.74; 95% confidence interval 1.06 to 2.95; p = 0.03; hazard ratio, 1.99; 95% confidence interval 1.13 to 3.64; p = 0.01). LVEF improvement was achieved in 69% of patients who underwent AF ablation, including 4% with late improvement. Lower LVESVI and higher e' could independently predict LVEF improvement.


Assuntos
Fibrilação Atrial/cirurgia , Velocidade do Fluxo Sanguíneo/fisiologia , Ablação por Cateter , Valva Mitral/fisiopatologia , Volume Sistólico/fisiologia , Disfunção Ventricular Esquerda/fisiopatologia , Idoso , Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/fisiopatologia , Diástole , Ecocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Prognóstico , Estudos Retrospectivos , Resultado do Tratamento , Disfunção Ventricular Esquerda/diagnóstico por imagem
20.
PLoS One ; 15(1): e0227651, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923919

RESUMO

We tested the influence of blood pressure variability on the reproducibility of dynamic cerebral autoregulation (DCA) estimates. Data were analyzed from the 2nd CARNet bootstrap initiative, where mean arterial blood pressure (MABP), cerebral blood flow velocity (CBFV) and end tidal CO2 were measured twice in 75 healthy subjects. DCA was analyzed by 14 different centers with a variety of different analysis methods. Intraclass Correlation (ICC) values increased significantly when subjects with low power spectral density MABP (PSD-MABP) values were removed from the analysis for all gain, phase and autoregulation index (ARI) parameters. Gain in the low frequency band (LF) had the highest ICC, followed by phase LF and gain in the very low frequency band. No significant differences were found between analysis methods for gain parameters, but for phase and ARI parameters, significant differences between the analysis methods were found. Alternatively, the Spearman-Brown prediction formula indicated that prolongation of the measurement duration up to 35 minutes may be needed to achieve good reproducibility for some DCA parameters. We conclude that poor DCA reproducibility (ICC<0.4) can improve to good (ICC > 0.6) values when cases with low PSD-MABP are removed, and probably also when measurement duration is increased.


Assuntos
Determinação da Pressão Arterial/métodos , Circulação Cerebrovascular/fisiologia , Homeostase/fisiologia , Adulto , Idoso , Pressão Arterial/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/fisiopatologia , Reprodutibilidade dos Testes
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